I would like to make some key points:
1. Plenty of crytpocurrencies have a limited supply, fiat currencies have an unlimited supply and consequently continue to depreciate.
2. Crytpocurrencies don't have tax demand, but essentially tax demand is the only thing supporting fiat (that continually depreciates) as fiat is the only 'legal' tender for paying taxes.
3. Some say cryptocurrency is nothing but digital 0s and 1s, but so is most fiat for years upon years now.
4. Cryptocurrencies are more liquid than stocks, bonds, and similar assets. To the best of my knowledge you can't get those funds today if you choose to liquidate, with crypto you can get it today.
5. Some cryptocurrencies may go bust, but so do companies, corporations, banks, and governments.
6. Cryptocurrencies are transactable assets. People can and do make purchases with crypto, they cannot with stocks or bonds.
7. To the best of my knowledge, cryptocurrencies present the fastest and cheapest way to transfer funds globally.
Finally, its my opinion that silver and gold are better MONEY (not currency) than fiat AND cryptocurrency.